The present invention relates to a power consumption economizer for refrigerating machines of the chiller type.
Currently, in order to cool an enclosed space by means of conditioning units using refrigerated water (fan coils), these conditioning units are fed with heat transfer fluid, typically water or water with the addition of glycol, which circulates from refrigerating machines of the so-called “chiller” type.
The hydraulic systems for such refrigerating machines are provided, on a same line, with pumping means adapted to propel a heat transfer fluid through a refrigeration exchanger of the heat transfer fluid, which merely consists in the evaporator of an associated refrigeration system for cooling the water.
A similar type of system is also provided with a free cooling device, known as “free cooling” in the jargon, for the heat transfer fluid.
Sensors for detecting the flow and temperature of the heat transfer fluid are associated with the pumping means, so that the inverter pump can modify its own operation to keep the flow-rate constant depending on the variations of the contrasting hydraulic load (i.e., variations in the contrasting pressure).
Although these refrigeration systems of the chiller type are widespread and appreciated, they have aspects that can be improved from the point of view of energy consumption.
The water flow is in fact propelled through the so-called evaporator, i.e., the heat exchange device for cooling the same water that then circulates in the conditioning units, even when the compressors of the evaporator are off because the water does not need to be cooled, i.e., when the cooling demand is nil, both if the thermal load is nil and if the thermal load is met by the refrigeration capacity of the free cooling exchanger.
This entails a significant expenditure of energy used by the pump to propel the water so as to overcome the load losses imposed by the flow of the water inside the evaporator.